1. Field of the Invention
The present invention relates to a thermal fatigue testing device and a recording medium recorded with a program.
2. Description of the Related Art
Conventionally, as a comparatively simple thermal fatigue testing method merely for evaluating a thermal fatigue life, a method is known that evaluates a thermal fatigue life by generating a temperature distribution at a test piece (test body) itself, and breaking the thermal fatigue test piece by a generated heat strain (for example, see Japanese Patent Application Laid-Open (JP-A) No. 60-249035). However, this method has a problem in that an entire test piece, which has a shape resembling an abacus bead, is heated and cooled, whereby states of a heat stress and a heat strain that accompanies a temperature cycle become complex, and it is not possible to quantitatively evaluate a thermal fatigue life.
In this regard, a thermal fatigue testing method and a thermal fatigue testing device that can address this problem have been proposed (for example, see JP-A No. 7-20031).
JP-A No. 7-20031 discloses a simple thermal fatigue testing method and thermal fatigue testing device which can be used in the evaluation of the thermal fatigue resistance of a metal material, a ceramic or the like, and in particular a light metal material. JP-A No. 7-20031 discloses a technique of performing a thermal fatigue test in which a test piece is held by a holder having a thermal expansion coefficient different to that of the test piece, and subjecting the entire test piece and holder to heating and cooling, and applying a desired strain to the test piece using the difference in thermal expansion between the holder and test piece. This technique is advantageous in terms of equipment cost and the like, since it is possible to apply a mechanical strain to a test piece without having to use an actuator. However, since a heating component and a cooling component are provided separately, there remains room for improvement in terms of reducing the size and complexity of a device. Further, since the entire test piece and holder are heated and cooled, a temperature non-uniformity is generated according to the thermal capacity of each component, and it is difficult to intentionally apply a desired temperature distribution to a test piece.
In order to address these issues, a thermal fatigue testing device that integrates a heating component and a cooling component such that it is smaller and simpler, and a thermal fatigue testing method that makes a temperature distribution of a test piece uniform, and that enables intentional application of a desired temperature distribution, have been proposed (for example, see Japanese Patent Application Laid-Open (JP-A) No. 9-178639).
JP-A No. 9-178639 discloses a thermal fatigue testing method that performs heating and cooling of a test piece (test body) using an air heater. Further, JP-A No. 9-178639 discloses a thermal fatigue testing device in which air is supplied by plural nozzles (six nozzles in JP-A No. 9-178639) according to a test piece and a holder that holds the test piece, thereby heating the test piece uniformly. JP-A No. 9-178639 discloses a thermal fatigue testing device that integrates a heating component and a cooling component to achieve an advantageous thermal fatigue testing device which is smaller and simpler, and discloses an advantageous thermal fatigue testing method that makes a temperature distribution of a test piece uniform, and enables intentional application of a desired temperature distribution.
Although the thermal fatigue testing device and thermal fatigue testing method disclosed in JP-A No. 9-178639 is advantageous as described above, in the thermal fatigue testing device disclosed in JP-A No. 9-178639, the air temperature used in the heating and cooling of the test piece is at or above room temperature, and it is difficult to reduce this air temperature to room temperature or less. Moreover, in the thermal fatigue testing device disclosed in JP-A No. 9-178639, since a large number of nozzles are necessary for use with respect to the test piece, the device structure is complex, and a large installation area is necessary in order to employ multiple test units. Considering the above, there is room for improvement of the thermal fatigue testing device and thermal fatigue testing method disclosed in JP-A No. 9-178639.
JP-A No. 9-178639 includes disclosure of temperature control, but there is a need for a faster, more accurate and more stable temperature control.